TY - BOOK
T1 - Catalytic Reduction of Oxygen by Metalloporphyrins in Fuel Cell Electrodes
AU - Elbaz, L.
AU - Bettelheim, Armand
AU - Korin, Eli
PY - 2006
Y1 - 2006
N2 - One of the main problems in today's fuel cells is
that the electrodes contain noble metal catalysts, such as
platinum. This raises the price of the fuel cell, thus
making it harder to introduce into the market. Another
major drawback is that the electrodes substrate material
consists of compressed carbon black particles. These
highly condensed particles impede the mass transport of
fuel or oxygen in the pores.
Aerogel carbon (AEC) is a porous conductive
material with relatively large surface area (approx.
600m2
/g). In this work, we describe a new concept based
on non-noble macrocyclic catalysts for O2 reduction and
their incorporation in AEC electrodes. Cobalt(III)-tetra(4-
sulfonatophenyl)porphyrin(CoTPPS), and cobalt(III)-
tetra(2-aminophenyl)porphyrin (CoToAPP) were
incorporated in AEC via adsorption (CoTPPS and
CoToAPP) or electropolymerization (CoToAPP). From
results obtained with SEM-EDS, the dispersion of the
cobalt porphyrins throughout the AEC cross section was
found to be uniform. Adsorption of the metalloporphyrins
was found to follow first order kinetics: kads = 2.8*10-5
sec-1 for both metalloporphyrins.
The electrocatalytic activity of these electrodes
towards the oxygen reduction reaction was investigated as
well. The half wave potentials obtained in air saturated 1
M H2SO4 solution for AEC, AEC/CoTPPS, and
AEC/CoToAPP electrodes were 75, 150, and 200mV vs.
Ag|AgCl, respectively. The current densities obtained for
these electrodes at 0V were 0.31, 0.82, and 1.32mA/cm2
,
respectively. Nafion was also incorporated in the AEC
pores and was found to be uniformly dispersed throughout
the electrode cross- section. This polymer blocked 30% of
the AEC micropores, but did not have any significant
effect on the surface area of the meso- and macro- pores.
The addition of Nafion enhanced proton migration in the
pores and consequently increased oxygen reduction
currents at 0 V in air saturated 1 M H2SO4: 0.5, 2.89, and
9.5mA/cm2
for AEC/Nafion, AEC/Nafion/CoTPPS, and
AEC/Nafion/CoToAPP electrodes, respectively
AB - One of the main problems in today's fuel cells is
that the electrodes contain noble metal catalysts, such as
platinum. This raises the price of the fuel cell, thus
making it harder to introduce into the market. Another
major drawback is that the electrodes substrate material
consists of compressed carbon black particles. These
highly condensed particles impede the mass transport of
fuel or oxygen in the pores.
Aerogel carbon (AEC) is a porous conductive
material with relatively large surface area (approx.
600m2
/g). In this work, we describe a new concept based
on non-noble macrocyclic catalysts for O2 reduction and
their incorporation in AEC electrodes. Cobalt(III)-tetra(4-
sulfonatophenyl)porphyrin(CoTPPS), and cobalt(III)-
tetra(2-aminophenyl)porphyrin (CoToAPP) were
incorporated in AEC via adsorption (CoTPPS and
CoToAPP) or electropolymerization (CoToAPP). From
results obtained with SEM-EDS, the dispersion of the
cobalt porphyrins throughout the AEC cross section was
found to be uniform. Adsorption of the metalloporphyrins
was found to follow first order kinetics: kads = 2.8*10-5
sec-1 for both metalloporphyrins.
The electrocatalytic activity of these electrodes
towards the oxygen reduction reaction was investigated as
well. The half wave potentials obtained in air saturated 1
M H2SO4 solution for AEC, AEC/CoTPPS, and
AEC/CoToAPP electrodes were 75, 150, and 200mV vs.
Ag|AgCl, respectively. The current densities obtained for
these electrodes at 0V were 0.31, 0.82, and 1.32mA/cm2
,
respectively. Nafion was also incorporated in the AEC
pores and was found to be uniformly dispersed throughout
the electrode cross- section. This polymer blocked 30% of
the AEC micropores, but did not have any significant
effect on the surface area of the meso- and macro- pores.
The addition of Nafion enhanced proton migration in the
pores and consequently increased oxygen reduction
currents at 0 V in air saturated 1 M H2SO4: 0.5, 2.89, and
9.5mA/cm2
for AEC/Nafion, AEC/Nafion/CoTPPS, and
AEC/Nafion/CoToAPP electrodes, respectively
UR - https://scholar.google.co.il/scholar?q=Catalytic+Reduction+of+Oxygen+by+Metalloporphyrins%2C+Lior+Elbaz+&btnG=&hl=en&as_sdt=0%2C5
M3 - Book
BT - Catalytic Reduction of Oxygen by Metalloporphyrins in Fuel Cell Electrodes
PB - Meeting Abstracts. No. 1. The Electrochemical Society
ER -